1.1 Technical Field
This invention pertains to the chemical removal of foreign material embedded in skin, generally referred to as a splinter. Such splinter removal involves the use of various pharmaceutical compositions useful in chemically removing the splinter from the skin, a method of using those chemical compositions for this purpose, and a bandage which includes the chemical composition to facilitate removal of a splinter.
1.2 Background Art
When foreign material becomes embedded in the epidermis, and in particular in the stratum corneum layer of the skin, that foreign material may be referred to as a splinter. The splinter causes injury to skin cells and pain, both upon entry and while the splinter remains embedded in the skin.
Commonly, splinters are removed by a mechanical tool, such as tweezers or a needle. One such device is shown in U.S. Pat. No. 2,451,994 to Towns. A splinter remover involving a pair of tweezers, with a reservoir for antiseptic, is described. The splinter remover allows the mechanical removal of a splinter, with the application of antiseptic by the same device.
The splinter removal methods known in the prior art all involve a significant detrimental effect: they are painful. Mechanical tools such as tweezers and needles, even when skillfully used, result in injury to surrounding skin cells in the stratum corneum layer of the skin, and activate pain sensations.
Removal of splinters by chemical means is not taught in the prior art. Various chemicals have been used to dissolve necrotic tissue caused by burning and to hasten the healing of burns. Application of such a chemical debriding agent is frequently accomplished by a bandage or other topical dressing. For example, U.S. Pat. No. 4,122,158 to Schmitt discloses a method of topically applying an antibacterial, antibiotic, antifungal or proteolytic agent in a polymer of a particular formula. Application of such an "agent-loaded" polymer to a burned surface by means of an absorbent carrier is described.
Similarly, U.S. Pat. No. 3,281,331 to Beggkvist teaches the use of a proteolytic enzyme for the treatment of wounds and debriding of third degree burns. Combining a proteolytic enzyme with an antibiotic in an ointment base and application by means of a bandage carrier is described.
U.S. Pat. No. 3,409,719 to Noe and Beckhorn discusses the use of a bacterial enzyme produced by the growth of Bacillus subtilis for the debridement of necrotic tissue. The enzyme may be prepared in ointment form for topical application.
An enzymatic composition comprising fibrinolysin and desoxyribonuclease, together with an antibiotic, is described as a debriding agent in U.S. Pat. 3,208,908 to Maxwell and Loomis. However, these patents do not teach the use of such debriding agents for the removal of foreign objects embedded in skin.
Removal of splinters through chemical debridement is most efficiently accomplished by incorporating the active chemical accomplishing the debridement into a bandage for application to the skin. U.S. Pat. No. 3,731,683 to Zaffaroni discloses a bandage design to allow the administration of controlled therapeutically effective quantities of topically active drugs. Among the drugs mentioned is salicylic acid. However, the patent emphasizes the unique controlled release rate of the bandage, and does not contemplate a particular use for the bandage with any particular chemical.
Other medicated bandages are known in the prior art for use in treating various skin disorders. U.S. Pat. No. 4,576,817 to Montgomery and Pellico discloses a bandage or pad incorporating an enzymatic material to inhibit bacterial growth. U.S. Pat. No. 2,602,042 to Abbott describes the preparation of a medical dressing incorporating a medication, such as an antibiotic substance, for treatment of burns or wounds.
Although the inventions described in these prior patents are effective for their intended purpose, none establishes a chemical method for the removal of splinters. The various chemical debriding agents and medicated bandages described above are designed to hasten healing after a severe burn or other wound is incurred. Polymers and enzymes, sometimes in conjunction with antibiotics, are used to dissolve necrotic tissue resulting from the catastrophe or burn. Any resulting desquamation effected by these chemicals and bandages involved only necrotic skin cells, and did not purport to effect any foreign material in the skin. Although these methods of treatment are analogous to the invention disclosed herein, none of these previous methods accomplishes the removal of splinters.
The mechanical method of splinter removal described in the Towns patent is effective for splinters close enough to the surface of the skin to be grasped with tweezers. However, this method can be quite painful, as well as injurious to viable skin cells.
Use of salicylic acid as a keratolytic agent is known in the prior art, for treatment of skin disorders other than splinter removal. Medical use of salicylic acid in dermatological cases is based on its action of solubilizing the intercellular cement that binds scales in the stratum corneum while increasing water binding, and thus hydrating the keratin. Although these chemical properties of salicylic acid have been reported in M. Davies and R. Marks, Br. J. Dermatol. 95: 187-192 (1976), R. Marks, M. Davies and A. Cattel, J. Invest. Dermatol. 64: 283 (1975), and C. Huber and E. Christophers, Arch. Derm. Res. 257, 294-97 (1977), these references do not explore the possible use of salicylic acid as a splinter removal agent.
The invention disclosed herein uses features of salicylic acid in particular medical compositions, in a manner not revealed in the prior art. The object of this invention is to provide a painless, effective method of removing splinters.